kokoro: update license-check.cfg to allow REUSE license updates

See changes in PR KhronosGroup#4256

This updates the license check configuration file to ignore the
license check for the license file metadata itself.
Also exclude local temporary files in .jj and .cipd, which helps
me with my local testing.

Author: dneto0

license-checker.cfg

@@ -15,6 +15,7 @@
 
                     "_config.yml",
                     ".*",
+                    ".*/**",
                     ".github/workflows/*.yml",
                     ".github/workflows/*.js",
                     ".jj/**",
@@ -23,6 +24,9 @@
                     "known_good.json",
                     "LICENSE.txt",
                     "make-revision",
+                    "standalone.gclient_entries",
+                    "LICENSES/*",
+                    "REUSE.toml",
                     "WORKSPACE",
 
                     "glslang/OSDependent/Web/glslang.*.js",